Merged neutral beams (EPJ Techniques and Instrumentation 2015, 2:10) by Andreas Osterwalder (EPFL, Switzerland) presents a detailed description of a merged beam apparatus for the study of low energy molecular scattering. In the experiment performed, a supersonic expansion of paramagnetic particles is merged with one of polar molecules, whilst a magnetic and an electric multipole guide are used to bend the two beams onto the same axis. Intended to inform any scientist who plans to construct a similar experiment, the article describes in detail how the apparatus was designed, characterised, and operated.

This is the first in a series of invited, tutorial-style review articles from key scientists in the field detailing the "nuts and bolts" of cold molecules, ions and collision experiments, meant both to educate beginning PhD students and to support new groups entering the field. The collection will continue to be maintained in the future to form an open-access knowledge base for the entire cold molecules community.